Increased contraction frequency in rat uterine strips treated in vitro with o,p'-DDT.

Elevated levels of DDT and other organochlorine pesticides have been associated with spontaneous abortion and preterm birth in several species, including humans (Delong et al. 1973; Hart et alo 1971; O'Leary et alo 1970; Saxena et al. 1980, 1981; Wassermann et al. 1982). Despite the prevalence of organochlorine pesticides in our environment, a mechanistic basis for this association has not been explored. Furthermore, while DDT has been associated with inhibition of calcium ATPases (Ghiasuddin and Matsumura 1981; Treinen and Kulkarni 1986), altered gap junctional communication (Madhukar et al. 1983; Davidson et al. 1985), and electrophysiological changes (Schefczik and Buff 1984; Beeman 1982), all of which could affect the excitation-contraction process characteristic of smooth muscle, direct effects of DDT on uterine smooth muscle have not been reported. This study was initiated to assess the direct effects of o,p'-DDT (an estrogenic isomer present in the technical grade preparation) on pregnant rat uterine tissue.